I left out the names.
I grew up surrounded by women. My dad died when I was 5 and my mother ended up moving me and my two younger sisters, back to live with her mother. For a long while another sister and her teenage daughters also lived with us. Me and seven women with friends sleeping over on the weekends. Seeing naked women or teenage girls in their underwear wandering around the house was fairly normal. When I hit puberty there was a real effort to minimize this, but it still happened a lot.
My mother never had 'the talk' with me. We never spoke directly about sex, ever. Everything I learned about sexuality was from friends, books and the pathetic sex-ed classes in middle school. Like most boys I had learned to masturbate when I was about 11 or 12 and did it often. I would masturbate early in the morning and then take a quick shower to clean up before the girls took over the bathroom we all shared. I spent a lot of time and effort looking at the many tampon and maxi-pad boxes in the bathroom. From going shopping I knew who used what product. I liked to try to figure out which girl was on her period. Sometimes I would jerk-off in the bathroom and cum onto a pad, knowing that my semen would touch a vagina.
One morning in the summer I was watching TV with my sister who was 13 at the time as one of my older cousins was getting ready to go to work. She had first walked by in a towel and later ran back to the bathroom in nothing but a t-shirt. I can remember seeing her bend over with her legs spread and I could see her vagina perfectly. I got hard and after she had left I began to masturbate while sitting on the sofa under a blanket thinking my sister could not see what I was doing. After a few moments, I was getting close to coming when my sister suddenly stood up and yanked on the corner of the blanket exposing my penis. Humiliated; I ran from the room and hid in my bedroom.
About half an hour later, my aunt knocked on my door saying she needed to talk with me. She said that it was perfectly normal for me to want to masturbate but that it was 'not cool' for me to do it in a common area in the house with my sister sitting right there. She also said that it was wrong for my sister to have done what she did and called her into my room and asked to apologize to me, which she did.
After a moment of awkward silence, my aunt asked if either of us had any questions about sex, as she knew my mom was unable to talk to us about it. My sister asked some sort of lame question, but that got my aunt going. She sat us both down on the bed and explained everything to us. She took off her clothes and sat with her legs open to show me all the parts of a woman's vagina. As soon as she did that I came in my pants. She said we could ask her anything, anytime. After they left I jerked-off again.
That night, both my younger sisters (14 and 13) came in to my room. They asked if I would show them my penis and jerk-off while they watched. I said I would if they did the same - show me yours and I'll show you mine. I got very turned on by this. I had never looked at either of them in a sexual way before although I knew the older sister had started her period as we had recently begun to buy 'slim' tampons.
For the first time, I looked at their bodies, hairless pussies and small breasts and I liked what I was seeing.
We all sat on the edge of the bed with me in the middle and I started to stroke myself. I tried to go slow, but I came in less than 30 seconds. My older sister was only going through the motions, but my younger sister lay back and fingered herself until she came. We all touched each other for a moment. I showed both girls how to masturbate me and let them do it, but I did not cum again. I was able to slide my fingers deep into my younger sister's vagina. As I was doing this my older sister said for me to stop as I had semen on my hands and this might get her pregnant. This put a damper on the whole situation and without saying a word the girls got dressed and left.
My sisters and I never did anything like that again but we did share secrets that other brothers and sisters may not have shared. For example; when my younger sister got her period I was the first person she told. Both of them told me about their 'first times' and other dating experiences. My first time was with a girl they knew very well and I was happy to have them tell me later that she thought I was a good lover.